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Biomedical subjects

D Snyder

Publications and source records attributed to D Snyder.

At least 37 records · Page 2Linked to original sources
PubMed1996

Assessment tools in psychiatry.

With the advent of managed care, administrators of mental health care will need to implement outcomes measurement systems that will provide information for cost control and quality improvement. These systems must take into account the changes occurring in the delivery of mental health care, such as the broad range of settings in which mental health care occurs, and allow for the measurement of outcomes over time. A useful system must also be flexible, allowing measures to tailor the system to individual needs. Two types of systems are currently being used. Simple systems measure general outcomes, such as patient satisfaction, at baseline and discharge. More complex systems are disorder-specific and can be used to compare different types of treatments or different groups of patients. The simple systems are less costly but are not as useful to quality improvement. The disorder-specific systems are more expensive, but the information gathered with these systems can be used in quality management. As implementation of these systems becomes more commonplace, challenges such as lack of standardization, patient reluctance to fill out forms, and the need for sensitive measurement instruments will need to be addressed.

Humans↗
PubMed1995

Perspectives on menopause.

Specific assumptions about knowledge lead directly to particular conceptualizations of menopause. The authors analyze the assumptions about menopause from biomedical, sociocultural, and feminist perspectives. In the process, how each perspective shapes research questions, research methodology, and interpretation of findings are discussed. The purpose of this article is to raise nurses' consciousness of consequences of basic philosophical assumptions on studies of menopause and knowledge generation.

Attitude to Health↗
PubMed1995

The Pinwheel Model of Bereavement.

The Pinwheel Model of Bereavement is a process-orientated model of grief which recognizes loss as a unique lived experience. The model and relevant nursing response are described using Margaret Newman's nursing theory of health as expanding consciousness. The model is based on research by Carter (1989) and clinical experience. The contextual theme for the model is "personal history." Six core themes are: being stopped, hurting, missing, holding, seeking, and valuing. Three meta themes are change, expectations, and inexpressibility. Capacities for "being with" the bereaved are identified for the practice of nursing.

Adaptation, Psychological↗
PubMed1995

Scintigraphic imaging with 123I-metaiodobenzylguanidine as a marker of cardiac adrenergic neurotransmission in the rat.

This study was performed to determine if 123I-metaiodobenzylguanidine (123I-MIBG) could be used to create scintigraphic images of the rat heart and to determine if this method could be used to estimate cardiac norepinephrine turnover in the intact animal. Male F344 rats were injected i.v. with 200-350 muCi of 123I-MIBG. Beginning at 5 min after the injection, scintigraphic images were made every 30 min for 5 h. The half-life of 123I-MIBG retention within the heart during the 5 h of the experiment was determined by plotting the log of the counts for each image vs. time. The half-life of cardiac 123I-MIBG was 3.44 +/- 0.17 h with a rate constant of 0.21 +/- 0.01 (hr-1). In a separate experiment, methacholine, a parasympathomimetic agonist, was given after the injection of 123I-MIBG and increased 123I-MIBG efflux. Cardiac 123I-MIBG uptake was reduced by 65% in rats sympathetically denervated with 6 hydroxy dopamine indicating that 123I-MIBG is accumulating for the most part in adrenergic nerve terminals. We conclude that scintigraphic imaging with 123I-MIBG may be a useful procedure for estimating cardiac adrenergic nervous system activity in the intact animal.

3-Iodobenzylguanidine↗
PubMed1994

Perceptions of preschoolers' vulnerability by mothers who had delivered preterm.

Assessed mothers who did and did not identify their children as vulnerable on a number of variables including perception of their child's behavior problems and their own sense of parental control. Children were also examined to determine their developmental abilities. Participants included 50 preschoolers who were born prematurely, their mothers, and their medical care providers. The mothers' response to the Vulnerable Child Scale was used to identify children as vulnerable and nonvulnerable. Mothers who perceived their children as vulnerable also rated them on the Child Behavior Checklist 2/3 as having more somatic problems and as being more aggressive, destructive, and poorly socialized. Additionally, these mothers expressed a diminished sense of parental efficacy and less control of their child's behavior as measured by the Parental Locus of Control Scale. However, results from the McCarthy Scales of Children's Abilities and the medical care provider's questionnaire revealed no differences between the groups of children. Overall findings suggest preschoolers born prematurely whose mothers perceive them as vulnerable are at risk for the Vulnerable Child Syndrome described by Green and Solnit (1964).

Adult↗
PubMed1993

Terminal acute myelogenous leukemia in a patient with congenital agranulocytosis.

Congenital agranulocytosis terminating in acute myelogenous leukemia has been previously reported in only two cases of adolescent males. We describe the clinical and laboratory features of a 13-year-old male with congenital agranulocytosis, treated with G-CSF with initial good neutrophil response, who subsequently developed acute myeloid leukemia. This rare complication may define a preleukemic subset of patients for whom G-CSF therapy is ineffective. The diagnostic challenges of this case are presented.

Adolescent↗
PubMed1991

Phorbol ester TPA inhibits the stimulation of bumetanide-sensitive Na+/K+/Cl- transporter by different mitogens in quiescent BALB/c 3T3 mouse fibroblasts.

In this study we examined the effect of the phorbol ester 12-O-tetradecanoyl-phorbol-13-acetate (TPA) on the bumetanide-sensitive Na+/K+/Cl- transporter in quiescent BALB/c 3T3 cells. We have shown that exposure of quiescent BALB/c 3T3 cultures to phorbol ester did not inhibit the basal bumetanide-sensitive Rb+ influx or efflux. In fact, at high concentration (100 ng/ml), TPA slightly stimulated the bumetanide-sensitive Rb+ influx and efflux. However, when the quiescent cultures were stimulated by serum or by defined growth factors, the stimulated fraction of the bumetanide-sensitive Rb+ influx was drastically inhibited by exposure of the cells to the phorbol ester TPA. Based on the above findings, we propose that activation of protein kinase C by the phorbol ester TPA does not inhibit the Na+/K+/Cl- cotransport activity; however it does suppress only the growth-factors-stimulated fraction of the cotransport in quiescent BALB/c 3T3 cells. These data propose that activation of kinase C has a regulatory feedback effect on the stimulation of the Na+/K+/Cl- cotransport activity by growth factors.

Animals↗
PubMed1991

Na+/K+/Cl- cotransport is stimulated by a Ca(++)-calmodulin-mediated pathway in BALB/c 3T3 fibroblasts.

In the present study, we investigated the role of intracellular Ca++ in the stimulation of the Na+/K+/Cl- cotransport in synchronized BALB/c 3T3 cells. The Na+/K+/Cl- cotransport was stimulated by the growth factors EGF, TGF-alpha, IGF-1, and IGF-2, which do not activate protein kinase C, but do induce a transient increase in free cytoplasmic Ca++. In addition, direct activation of protein kinase C by the phorbol ester 12-O-tetradecanoyl-phorbol-13-acetate (TPA) did not affect the Na+/K+/Cl- cotransport activity of quiescent cells. The Na+/K+/Cl- cotransport was also stimulated by the above mitogens in cells pretreated with the phorbol ester TPA. This treatment led to a progressive decline in the activity of cellular protein kinase C. This result implies that cells deficient in protein kinase C may still support stimulation of the Na+/K+/Cl- cotransport. Taken as a whole, these findings suggest that the Na+/K+/Cl- cotransport is stimulated predominantly by a protein kinase C-independent mechanism in BALB/c 3T3 fibroblasts. Both the intracellular Ca++ antagonist 8-(N,N-diethylamino)octyl-3,4,5-trimethoxybenzoate (TMB-8) and two potent calmodulin antagonists, trifluoperazine (TFP) and chloropromazine (CP), blocked serum- and mitogen-stimulated Na+/K+/Cl- cotransport. These results suggest that the Na+/K+/Cl- cotransport is stimulated by an increase of intracellular Ca++ and subsequently by a Ca(++)-calmodulin-mediated pathway in the synchronized BALB/c 3T3 fibroblasts.

3T3 Cells↗
PubMed1991

Caloric restriction affects liver microsomal monooxygenases differentially in aging male rats.

Caloric restriction (CR) extends life span and retards the onset of physiological changes and pathologies associated with aging, but the underlying mechanisms remain unresolved. This study demonstrates that CR postpones the documented age-related declines in and/or enhances the activity and microsomal concentration of several liver monooxygenases in male rats, i.e., NADPH cytochrome P-450 reductase, total cytochromes P-450. However, the relative concentration of cytochrome P-450b+C did not exhibit statistically significant changes, whereas another isozyme, the male specific P-450h, declined significantly in both ad libitum-fed and CR rats as a function of increasing age. While CR appears to retard age-associated changes in certain liver enzymes, this effect is by no means universal. The hepatic monooxygenases constitute a well-characterized enzyme system in which to examine the perturbation of the aging process by CR.

Aging↗
PubMed1991

The spectrum of molecular alterations in the evolution of chronic myelocytic leukemia.

DNA from 135 patients with chronic myelogenous leukemia (CML) at various clinical stages and Philadelphia (Ph1) chromosome positive acute lymphoblastic leukemia was investigated for alterations in a variety of proto-oncogenes which have been implicated in the evolution of CML from its chronic phase to blast crisis. The most common genetic change found in the evolution of typical Ph1 chromosome positive CML to blast crisis was an alteration of the p53 gene involving either a rearrangement, a deletion, or a point mutation in the coding sequence of the gene. Alterations of the p53 gene were found in the myeloid and the rare megakaryocytic variant of blast crisis but were absent in the lymphoid leukemic transformants. Gross structural alterations were seen in 11 of 54 (20%) of myeloid or unknown phenotypes of blast crisis and in only 1 of 44 chronic phase cases. Eight examples of mutations in the open reading frame of the p53 gene at codons 49, 53, 60, 140, 202, 204, 238, and 239 were observed in blast crisis patients. Mutations in the N-RAS gene were rare in typical blast crisis (2 of 27 cases) but were found in megakaryocytic and Ph1 negative myeloid blast crisis. We concluded that heterogeneous alterations in the p53 gene and occasionally in the N-RAS genes accompany the evolution of chronic phase CML to blast crisis.

Blotting, Northern↗
PubMed1990

Role of the Na+/K+/Cl- transporter in the positive inotropic effect of ouabain in cardiac myocytes.

In this study we have characterized the bumetanide-sensitive K+/Na+/Cl- cotransport in cultured rat cardiac myocytes. 1) It carries about 10% of the total K+ influx. 2) It is sensitive to furosemide (Ki0.5 = 10(-6)M) and bumetanide (Ki0.5 = 10(-7)M). 3) It is strongly dependent on the extracellular concentrations of Na+ and Cl-. 4) It carries out influx of both ions, K+ and Na+. A therapeutic concentration of ouabain (10(-7) M) stimulated the bumetanide-sensitive K+ influx (as measured by 86Rb+), in the cultured myocytes, with no effect on the bumetanide-resistant K+ influx, which was mediated mostly by the Na+/K+ pump. Stimulation of the bumetanide-sensitive Rb+ influx by a low ouabain concentration was strongly dependent on Na+ and Cl- in the extracellular medium. A low concentration of ouabain (10(-7) M) was found to increase the steady-state level of cytosolic Na+ by 15%. This increase was abolished by the addition of bumetanide or furosemide. These findings suggest that ouabain, at a low (10(-7) M) concentration, induced its positive inotropic effect in rat cardiac myocytes by increasing Na+ influx into the cells through the bumetanide-sensitive Na+/K+/Cl- cotransporter. In order to examine this hypothesis, we measured the effect of bumetanide on the increased amplitude of systolic cell motion induced by ouabain. Bumetanide or furosemide, added to cultured cardiac myocytes, inhibited the increased amplitude of systolic cell motion induced by ouabain. Neither bumetanide nor furosemide alone has any significant effect on the basal amplitude of systolic cell motion. We propose that stimulation of bumetanide-sensitive Na+ influx plays an essential role in the positive inotropic effect in rat cardiac myocytes induced by low concentration of ouabain.

Animals↗
PubMed1990

Light-harvesting proteins of diatoms: their relationship to the chlorophyll a/b binding proteins of higher plants and their mode of transport into plastids.

We have cloned and characterized members of a gene family encoding polypeptide constituents of the fucoxanthin, chlorophyll a/c protein complex, a light-harvesting complex associated with photosystem II of diatoms and brown algae. Three cDNA clones encoding proteins associated with this complex in the diatom Phaeodactylum tricornutum have been isolated. As deduced from the nucleotide sequences, these light-harvesting proteins show homology to the chlorophyll a/b binding polypeptides of higher plants. Specifically, the N-terminal regions of the fucoxanthin, chlorophyll a/c-binding proteins are homologous to the chlorophyll a/b binding proteins in both the third membrane-spanning domain and the stroma-exposed region between membrane-spanning domains 2 and 3. Like the chlorophyll a/b-binding proteins, the mature fucoxanthin, chlorophyll a/c polypeptides have three hydrophobic alpha-helical domains which could span the membrane bilayer. The similarities between the two light-harvesting proteins might reflect the fact that both bind chlorophyll molecules and/or might be important for maintaining certain structural features of the complex. There is little similarity between the N-terminal sequences of the primary translation products of the fucoxanthin, chlorophyll a/c proteins and any transit sequences that have been characterized. Instead, the N-terminal sequences have features resembling those of signal sequences. Thus either transit peptides used in P. tricornutum show little resemblance to those of higher plants and green algae or the nuclear-encoded plastid proteins enter the organelle via a mechanism different from that used in higher plants.

Amino Acid Sequence↗
PubMed1990

Ectopic pregnancy in adolescents: a clinical review for pediatricians.

Pediatricians caring for sexually active female adolescents and young adults need to be aware of the history, symptoms, and signs of an ectopic pregnancy. A thorough history and physical examination, including the pelvic examination, as well as specific diagnostic tests such as repeated quantitative hCG measurements, and ultrasonography when indicated, are crucial to proper and early diagnosis of a nonruptured ectopic pregnancy manageable by laparoscopy. The key to early diagnosis is to include ectopic pregnancy in the differential diagnosis in any sexually active female patient who has abnormal vaginal bleeding or abdominal pain. With early diagnosis, close observation, and appropriate management, the outcome is more likely to be favorable, with minimal morbidity and risk of death.

Adolescent↗
PubMed1990

Antigenic characterization of IBDV field isolates by their reactivity with a panel of monoclonal antibodies.

Recently Infectious Bursal Disease Virus isolates have been described in USA displaying an antigenic drift. Many of the new isolates were very virulent for chickens. In several European countries severe outbreaks of Gumboro disease have also been reported from vaccinated and non-vaccinated flocks. Since vaccinated SPF birds were shown to be protected against challenge infection with the new isolates under laboratory conditions, a more detailed investigation of the European isolates is wanted. The similarity between the European and US field situation got us to use a panel of monoclonal antibodies (MCAs) previously applied to characterize US strains for testing European isolates. An antigen capture ELISA has been carried out directly on bursa homogenates of chickens form the field. One European (F52/70) and two US (Var. E and GLS-5) strains have been included as reference viruses. From the results presented here it can be concluded that the European isolates (Netherlands, France, UK, Germany, Jugoslavia and Spain) did not undergo the same antigenic drift as the US strains. A more extensive analysis of the isolates will be done to elucidate their role for disease outbreaks.

Animals↗
PubMed1989

Prevention of prostate cancer and liver tumors in L-W rats by moderate dietary restriction.

Aging conventional (CV) and germfree Lobund-Wistar (L-W) rats developed spontaneous tumors, predominantly in the prostate, liver, and adrenal glands. In CV L-W rats a 30% reduction of daily intake (natural ingredient diet L-485) had the following effects: (1) reduction of the incidence of metastatic prostate adenocarcinomas (PA) from 25.7% to 6.3% and extension of the average latent periods from 26.6 to 36.7 months; and (2) reduction of the incidence of hepatomas from 59% to 26% and extension of the average latent periods from 31.3 to 34 months. Adrenal medullary tumors developed in approximately 60% of rats older than 19 months, regardless of dietary intake and microbial status. Stromal hyperplasia developed among 36 of 78 (46%) rats older than age 30 months. Rats with PA were free of stromal hyperplasia, and the reverse was also true. Germfree L-W rats developed all of the above tumors, but the diet-related differences were not as significant as those among the conventional counterpart rats. The incidence of prostatis was reduced from 22% to 6% among the diet-restricted rats, but this lesion did not develop among the germfree rats.

Adenocarcinoma↗